Such an embellisher is generally employed to adapt a lamp of any particular size for mounting in a housing which is provided in part of the bodywork of an automotive vehicle, since the dimensions of the housing may vary according to what vehicle is to be equipped with the lamp.
In most cases, the embellisher is in the form of a tubular hollow body having a flange portion and a base where the base has an aperture or window; the shape and dimensions of the window correspond to the shape and dimensions of the front face of a lamp around which the embellisher is to be fitted. The lamp and the embellisher are secured to the vehicle housing by any appropriate means, preferably in such a way that the front face of the lamp, which will normally be defined by the lens, lies flush in the window of the embellisher.
The lamp glass conventionally has ribs, at least some of which have the function of ensuring correct distribution of the light beam emitted by the lamp. For aesthetic reasons, it is common to provide reliefs on the base of the embellisher. These reliefs provide a visual effect which continues that of the ribs on the lens. The reliefs are usually aluminised so as to confer on the lamp the appearance of a reflector seen through the lens.
In order to protect the reliefs from becoming clogged with dirt, the reliefs are formed on an internal or inner face of the base of the embellisher, lying inside the space defined by the cylindrical hollow body of the embellisher so that the inner face is thus enclosed. Such an embellisher is made of transparent plastics material, with an aluminium layer deposited by vacuum metalisation on the inner face.
The above arrangements, which enable a satisfactory aesthetic effect to be obtained, do involve difficulties in manufacture which can lead to unacceptable wastage, unless complex and tiresome techniques are adopted in the metalising process. In particular, it is especially difficult to repeatedly provide correct and uniform coatings by vacumetalisation on reliefs which lie within a tubular enclosure, or in other words within the interior of a concave member.